The present invention relates to a manual control device for adjusting the control of various manipulated variables by the touch of a hand.
Heretofore, as a device of this type there has been used a control device as shown in FIG. 1. Referring to the figure, a main body of a manual control device 10 is provided with a set value indicator (SV indication) 12 for indicating desired values and a manipulated value indicator (MV indication) 13 for indicating the present value, by which the set value and the manipulated value are respectively indicated in the form of a bar graph. The main body 10 is also provided with an incremental touch key 14 and a decremental touch key 15 for the manipulated-value indicating bar 13. When the touch key 14 or 15 is activated by a hand or a finger, the indicated value on the indication bar 13 is increased or decreased, that is raised or lowered, respectively. Further, the main body 10 is provided with an acceleration touch key 16. When one of the touch key 14 or 15 is touched simultaneously with this acceleration touch key 16, the changing rate of the indication bar 13 is increased or decreased, respectively.
According to the construction of FIG. 1, in a case where the present value of the manipulated value greatly deviates from the desired value of the set value, in order to bring the manipulated value on the indication bar 13 into agreement with the set value on the indication bar 12, the incremental touch key 14 or the decremental touch key 15, is simultaneously activated with the acceleration touch key 16 to accelerate the adjustment of the manipulated value towards the setting of the set value. When the manipulated value has come close to the set value, the hand is released from the acceleration key 16 while either the touch key 14 or 15 is held activated until the manipulated value indicated by the indication bar 13 agrees with the set value indicated by the indication bar 12.
Since the prior-art device is constructed and operated as described above, the acceleration touch key 16 which is separate from the ordinary touch keys 14 and 15 must be disadvantageously provided in order to change the manipulated value at a high rate. Another disadvantage is that, when the key 14 or 15 is activated, the key 16 must also be simultaneously touched, and the operator is sometimes forced to use both his hands.